As the nation prepares to mark the 20th anniversary of the September 11th, 2001 attack on America, most of the media coverage will address the tremendous human costs of the 9/11 atrocity and the U.S. response to it. In one section of his Brookings article, “How America’s response to 9/11 contributed to our national decline,” William A. Galston also summarized the economic and political costs of America’s longest war:

The opportunity costs of our post-9/11 policy choices have been enormous. Since 2001, the United States has spent about $2 trillion in direct warfighting costs in Iraq and Afghanistan. One estimate places the total cost at $4 trillion, not counting the “long tail” outlays for treating the physical and mental damage these wars have inflicted on thousands of the best men and women our country has to offer.

It would be naïve to suggest that all this money would otherwise have been put to productive use in domestic public policy or the private sector. But one thing is clear: During years of fiscal restraints on discretionary spending during the past decade, our wars in the Middle East received funding from accounts to which the official budget limits did not apply.

Because domestic policy had no such safety valve, important government functions suffered, including the emergency health stockpile that was all but empty when we needed it the most in the early months of the pandemic.  At the same time, our failure to raise taxes to fund our post-9/11 military engagements wars guaranteed steady upward pressure on the national debt. A more measured response to the attack on our homeland would have made us stronger at home, with no loss of security. This alternative course, moreover, would have given the Department of Defense more bandwidth to focus on the military modernization needed to counter the great-power threats we now face.

Galston is critical of “manner of our withdrawal from Afghanistan,” but concludes that “we cannot afford to squander our energy in endless “Who lost Kabul?” debates. We should close the book on the 9/11 era, confine our policies in the Middle East to defending our friends and our essential interests, and focus instead on the task before us—doing what is necessary at home and abroad to arrest our decline and remain fully competitive in the struggle to define world order in the 21st century.”